Clinical significance of complement deficiencies
H David Pettigrew1, Suzanne S Teuber, M Eric Gershwin
1Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis School of Medicine, Davis, California 95616, USA.
Annals of the New York Academy of Sciences
|September 18, 2009
Summary
Complement deficiencies, impacting innate and adaptive immunity, are linked to various diseases, from recurrent infections to autoimmune disorders. Understanding these deficiencies is crucial for diagnosing and managing complex health conditions.
Area of Science:
- Immunology
- Genetics
- Pathology
Background:
- The complement system, comprising over 30 proteins, is vital for innate and adaptive immunity.
- Complement deficiencies were historically linked to recurrent childhood infections but are now associated with a wider range of diseases.
- Increased understanding of the complement system has revealed its role in numerous pathologies beyond infection susceptibility.
Purpose of the Study:
- To elucidate the diverse clinical manifestations of complement system deficiencies.
- To correlate specific complement pathway deficiencies with associated diseases and infection risks.
- To review the inheritance patterns of various complement-associated genetic disorders.
Main Methods:
- Review of existing literature on complement system function and deficiencies.
- Analysis of clinical data linking complement pathway defects to specific diseases.
- Categorization of complement deficiencies based on affected pathways and inheritance patterns.
Main Results:
- Classical pathway deficiencies increase susceptibility to encapsulated bacteria and lupus-like syndromes.
- Mannose-binding lectin pathway deficiencies are linked to increased bacterial infections.
- Alternative and terminal pathway deficiencies are associated with Neisseria infections, while Factor H deficiency can cause glomerulonephritis and HUS.
- Specific deficiencies like CD18 (leukocyte adhesion deficiency type 1) and CD59 (paroxysmal nocturnal hemoglobinuria) have distinct clinical outcomes.
- Most complement deficiencies are autosomal recessive, with exceptions including X-linked recessive properidin deficiency and autosomal dominant C1 inhibitor deficiency.
Conclusions:
- Complement deficiencies present a wide spectrum of clinical symptoms, reflecting the system's complexity.
- Deficiencies in different complement pathways confer distinct risks for infections and autoimmune diseases.
- Understanding the genetic basis and inheritance patterns of complement deficiencies is essential for clinical management.
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